1. Field of the Invention
The present invention relates to a system for restoring control features of a television receiver normally lost when an external tuning device, such as a cable converter, is used in conjunction with the receiver. Normally, the television receiver is then tuned to an empty channel, while the external tuning device receives the incoming signal, converts its carrier to the empty channel carrier and transmits this signal to the television receiver. Since the television receiver is permanently tuned to the empty channel, channel associated features such as parental control, on screen display of the channel being received, etc. are rendered inactive.
2. Background
U.S Pat. No. 4,386,436 describes a system in which a portion of the receiver system is used to control an external appliance through the AC power supply line. The user enters an appliance control command into the keyboard. The appliance control command is encoded and modulated onto a carrier signal which is transmitted on the AC power supply line. The AC power supply to the external appliance is controlled by an external appliance control module located near the appliance and responsive to the control command from the television receiver.
U.S. Pat. No. 4,529,980 a receiver-transmitter arrangement for controlling, for example, a garage door opening can send a code generated in the receiver to the transmitter by means of a light emitting diode.
Neither of these patents relate to restoring the channel associated functions in a television tuning system while an external tuning device is in use.